1. Field of the Invention
The present invention relates in general to equipment for impact tests on plastic materials. More precisely, the invention relates to a hammer for a Charpy pendulum. As is known, the Charpy pendulum is a measuring instrument that is basically made up of a supporting structure having a rotating shaft with horizontal axis, fixed to which is a hammer that has the purpose of striking a specimen with a preset energy. The hammer must be designed and built so as to approximate as accurately as possible the behaviour of an ideal pendulum having an equivalent mass concentrated in the point of impact with the specimen.
2. Description of the Related Art
In traditional solutions, the hammer comprises a metal block fixed to the end of a rod that constitutes the arm of the hammer. The traditional solutions derive from the need to position the centre of gravity of the hammer at the point of impact of the head. Traditionally, the arm of the hammer is formed by a relatively thin rod with a weight as small as possible with respect to the weight of the head.
The known solutions involve difficulties from the production standpoint, in particular since they require three different components (the head, the rod, and a device for fixing the rod to the shaft of the pendulum) that must be fixed to one another with high precision.